From: Filip Bozuta <Filip.Bozuta@syrmia.com>
To: Leif N Huhn <leif.n.huhn@gmail.com>, qemu-devel@nongnu.org
Subject: Re: [PATCH 1/1] linux-user: Add support for SG_IO and SG_GET_VERSION_NUM raw SCSI ioctls
Date: Fri, 31 Jul 2020 12:23:23 +0200 [thread overview]
Message-ID: <2b0db8d3-cd3a-4f62-1f90-8554c6195686@syrmia.com> (raw)
In-Reply-To: <20200730025548.237905-2-leif.n.huhn@gmail.com>
On 30.7.20. 04:55, Leif N Huhn wrote:
> This patch implements functionalities of following ioctls:
>
> SG_GET_VERSION_NUM - Returns SG driver version number
>
> The sg version numbers are of the form "x.y.z" and the single number given
> by the SG_GET_VERSION_NUM ioctl() is calculated by
> (x * 10000 + y * 100 + z).
>
> SG_IO - Permits user applications to send SCSI commands to a device
>
> It is logically equivalent to a write followed by a read.
>
> Implementation notes:
>
> For SG_GET_VERSION_NUM the value is an int and the implementation is
> straightforward.
>
> For SG_IO, the generic thunk mechanism is used, and works correctly when
> the host and guest architecture have the same pointer size. A special ioctl
> handler may be needed in other situations and is not covered in this
> implementation.
>
> Signed-off-by: Leif N Huhn <leif.n.huhn@gmail.com>
> ---
> linux-user/ioctls.h | 2 ++
> linux-user/syscall.c | 1 +
> linux-user/syscall_defs.h | 33 +++++++++++++++++++++++++++++++++
> linux-user/syscall_types.h | 5 +++++
> 4 files changed, 41 insertions(+)
>
> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index 0713ae1311..92e2f65e05 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -333,6 +333,8 @@
> IOCTL(CDROM_DRIVE_STATUS, 0, TYPE_NULL)
> IOCTL(CDROM_DISC_STATUS, 0, TYPE_NULL)
> IOCTL(CDROMAUDIOBUFSIZ, 0, TYPE_INT)
I think there should be a space between ioctls of different groups (in
this case CDROM and SG).
> + IOCTL(SG_GET_VERSION_NUM, 0, TYPE_INT)
SG_GET_VERSION_NUM reads the SG driver version number which means it is of
type IOC_R. The 0 is used only for ioctl types that don't have the third
argument. Also,
the third argument is a pointer to a 'TYPE_INT' since it is used for
reading. I tried
your patch with sg_simple1 and I get the different version number with
native and
cross execution so I think this needs to be corrected. The IOCTL(...)
definition should be:
IOCTL(SG_GET_VERSION_NUM, IOC_R, MK_PTR(TYPE_INT))
After this, the 'SG_GET_VERSION_NUM' works fine.
> + IOCTL(SG_IO, IOC_RW, MK_PTR(MK_STRUCT(STRUCT_sg_io_hdr)))
>
> #if 0
> IOCTL(SNDCTL_COPR_HALT, IOC_RW, MK_PTR(TYPE_INT))
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 945fc25279..d846ef1af2 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -115,6 +115,7 @@
> #ifdef HAVE_DRM_H
> #include <libdrm/drm.h>
> #endif
> +#include <scsi/sg.h>
> #include "linux_loop.h"
> #include "uname.h"
>
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 3c261cff0e..0e3004eb31 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -2774,4 +2774,37 @@ struct target_statx {
> /* 0x100 */
> };
>
> +/* from kernel's include/scsi/sg.h */
> +
> +#define TARGET_SG_GET_VERSION_NUM 0x2282 /* Example: version 2.1.34 yields 20134 */
> +/* synchronous SCSI command ioctl, (only in version 3 interface) */
> +#define TARGET_SG_IO 0x2285 /* similar effect as write() followed by read() */
> +
> +struct target_sg_io_hdr
> +{
> + int interface_id; /* [i] 'S' for SCSI generic (required) */
> + int dxfer_direction; /* [i] data transfer direction */
> + unsigned char cmd_len; /* [i] SCSI command length */
> + unsigned char mx_sb_len; /* [i] max length to write to sbp */
> + unsigned short iovec_count; /* [i] 0 implies no scatter gather */
> + unsigned int dxfer_len; /* [i] byte count of data transfer */
> + abi_ulong dxferp; /* [i], [*io] points to data transfer memory
> + or scatter gather list */
> + abi_ulong cmdp; /* [i], [*i] points to command to perform */
> + abi_ulong sbp; /* [i], [*o] points to sense_buffer memory */
> + unsigned int timeout; /* [i] MAX_UINT->no timeout (unit: millisec) */
> + unsigned int flags; /* [i] 0 -> default, see SG_FLAG... */
> + int pack_id; /* [i->o] unused internally (normally) */
> + abi_ulong usr_ptr; /* [i->o] unused internally */
> + unsigned char status; /* [o] scsi status */
> + unsigned char masked_status;/* [o] shifted, masked scsi status */
> + unsigned char msg_status; /* [o] messaging level data (optional) */
> + unsigned char sb_len_wr; /* [o] byte count actually written to sbp */
> + unsigned short host_status; /* [o] errors from host adapter */
> + unsigned short driver_status;/* [o] errors from software driver */
> + int resid; /* [o] dxfer_len - actual_transferred */
> + unsigned int duration; /* [o] time taken by cmd (unit: millisec) */
> + unsigned int info; /* [o] auxiliary information */
> +}; /* 64 bytes long (on i386) */
> +
This target structure is defined, but is not used anywhere. It should be
used
in a special ioctl handling function for SG_IO to convert the values of
'sg_io_hdr'
between host and target.
> #endif
> diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h
> index 3f1f033464..3752d217e2 100644
> --- a/linux-user/syscall_types.h
> +++ b/linux-user/syscall_types.h
> @@ -59,6 +59,11 @@ STRUCT(cdrom_read_audio,
> TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_INT, TYPE_PTRVOID,
> TYPE_NULL)
>
> +STRUCT(sg_io_hdr,
> + TYPE_INT, TYPE_INT, TYPE_CHAR, TYPE_CHAR, TYPE_SHORT, TYPE_INT, TYPE_PTRVOID,
> + TYPE_PTRVOID, TYPE_PTRVOID, TYPE_INT, TYPE_INT, TYPE_INT, TYPE_PTRVOID, TYPE_CHAR,
> + TYPE_CHAR, TYPE_CHAR, TYPE_CHAR, TYPE_SHORT, TYPE_SHORT, TYPE_INT, TYPE_INT, TYPE_INT)
> +
I think a nicer and cleaner way to define the thunk types is to write
the types in separate lines
followed by a tail comment which describes the field type. Something like:
STRUCT(sg_io_hdr,
TYPE_INT, /* interface_id */
TYPE_INT, /* dxfer_direction */
TYPE_CHAR, /* cmd_len */
...
This way it is less likely that an issue can ocurr (i.e. to forget a
field) and it makes the
code more reviewable. You can check out other examples from
'syscall_types.h' (i.e. snd_timer_id,
loop_info).
Best regards,
Filip
> STRUCT(hd_geometry,
> TYPE_CHAR, TYPE_CHAR, TYPE_SHORT, TYPE_ULONG)
>
next prev parent reply other threads:[~2020-07-31 10:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 2:55 [PATCH 0/1] linux-user: Add support for SG_IO and SG_GET_VERSION_NUM raw SCSI ioctls Leif N Huhn
2020-07-30 2:55 ` [PATCH 1/1] " Leif N Huhn
2020-07-31 10:23 ` Filip Bozuta [this message]
2020-07-31 9:40 ` [PATCH 0/1] " Filip Bozuta
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